Hue-plane preserving colorimetric characterization methods for digital cameras are known, and e.g. Danish patent application DK 2005 00666 discloses one such colorimetric characterization method.
US 2015116738 and CN 104601858 relates to an image forming apparatus and a color value conversion method.
Further colorimetric characterization methods for digital cameras are described e.g. in WO 2013/131311 and U.S. Pat. No. 5,398,124.
The prior art does not disclose the presently claimed principles of optimization and improved differentiability of color channel value transformations incorporating Hue-plane preserving colorimetric characterization methods.